A model floats in a tank at Vancouver's Float House. Normally, customers are naked and the tanks are pitch black. (Float House)

Rich Workman didn't know what to expect the first time he tried a sensory deprivation float tank.

He had a gift certificate from a charity auction and climbed into the warm salty waters of Vancouver's Float House for a break on a Friday afternoon.

"It felt like I was lying in bed at first, and then it just felt like the bed dropped away."

Before leaving, he bought two more sessions.

Float therapy, once a craze of the 80s, is again growing rapidly in Canada, fuelled in part by celebrity endorsements and a desire to unwind.

For the industry to last this time, a key will be attracting floaters back after their first 'whoa' moment.

A float tank at Float House's Gastown location. Closing the hatch for total darkness is optional (Lisa Johnson/CBC)

'I was a little anxious'

Float House co-owner Mike Zaremba remembers his first float, in a massage therapist's basement in Coquitlam, B.C.

"At first I was a little anxious," Zaremba said. "It's a very strange thing to go into a dark space with water ... that environment does not exist anywhere else on Earth where we have maximal sensory reduction."

Float tanks are usually white, made of fibreglass, and designed to block out the world.

At Float House, each tank sits in a private room, where the user strips and showers alone, before climbing in. Closing the hatch for total darkness is optional.

Inside, the water is about ankle-deep, heated to skin temperature, and loaded with about a tonne of Epson salt — making it so dense a person is buoyant without effort.

"It felt like I was in my mom's womb," said first-time floater Nayling Materan.